Various methods have heretofore been proposed for allowing a viewer to view an image stereoscopically. For example, Patent Document 1 discloses a method for displaying a synthesized image composed of right-eye and left-eye images with parallax on a display device, and allowing the viewer's right-eye to see only the right-eye image and the viewer's left-eye to see only the left-eye image. According to this method, the viewer is able to perceive a sense of depth that depends on the amount of parallax between the right-eye and left-eye images (hereinafter, “horizontal parallax”).
Patent Document 1: JP 2002-123842A (paragraphs 0002 and 0005)